1. Molecular and Computational Biology, Department of Biological Sciences, University of Southern California, Los Angeles, California 90089
2. University of Tennessee, Health Science Center, Memphis, Tennessee 38163
3. Texas A & M, Veterinary Medicine and Biomedical Sciences, College Station, Texas 77845
4. The Jackson Laboratory, Bar Harbor, Maine 04609
5. Loyola University, Department of Biology, Chicago, Illinois 60626